Any luck with 6SL7's....microphonics?

[NatStrat79]

Lately I've been messing around with a couple of early Ampegs that both came to me with Sylvania 6SL7's most of them are to a certain extent microphonic. I also purchased a couple NOS Sylvanias from a reputable online seller, I won't name any names but will say this seller has always been great to work with and I will buy from them again. Even the NOS 6SL7's I purchased went microphonic over a period of about 6 months. One of them even to the point where it howls and is now unusable. Has anyone had any luck with specific brands of 6SL7's that aren't as prone to microphonics? I need to scrounge up about 5 of them without breaking the bank.

[marscottm]

I got some NOS/JAN 5691? (6SL7) tubes from Angela awhile back and they've been fine

[2tones]

The RCA Special Red 5691 is also a pretty good choice. Triple micas to support the internal structure, and a red micanol base. They're rated at 10,000 hours - or about 13 years at a couple of hours per day.

They're the same tube even if they don't say "JAN-CRC" (the military designation for RCA). Just look for the red base.

[dorianadams]

Originally Posted by 2tones

The RCA Special Red 5691 is also a pretty good choice. Triple micas to support the internal structure, and a red micanol base. They're rated at 10,000 hours - or about 13 years at a couple of hours per day.

They're the same tube even if they don't say "JAN-CRC" (the military designation for RCA). Just look for the red base.

These are good but $80 or so apiece at this point (also the longer they have been around the more they have been selected through). Have you tried the Tung Sol reissue at $12.00? Worth a shot...
http://www.boiaudioworks.com/index.p...FQHmgAod6myt4g

[NatStrat79]

I might try the tung sol reissue. While the RCA red bases look great I cant afford nearly 80 a piece when I need five of them and with regular NOS going for about 25 to 30 I cant justify spending over $100 on NOS that may or may not go microphonic in a few months time. Has anyone actually tried the Tungsol ri 6sl7?

[SLG]

You might try some NOS Tung-Sol 6SU7-GTY. These were an industrial version of the 6SL7, and have matched triodes. Tung Sol was the only company that actually manufactured the 6SU7, but occasionally you find them relabeled GE. The TS 6SU7-GTY was an excellent tube, and can usually be found at a good price because most people don't know what there are. Now the cat's out of the bag.